High-velocity rudder

ABSTRACT

A rudder, especially for water vessels, which in its one end is connected with the vessel&#39;s hull ( 1 ) and comprising a main rudder blade ( 3 ) and rudder flaps ( 5, 6 ) arranged to be turnable with respect to the main rudder blade ( 3 ). The new traits of the invention are that the main rudder blade ( 3 ) is arranged to be in a fixedly anchored centre position with respect to the hull ( 1 ), and having two or more rudder flaps ( 5, 6 ) mounted leading and trailing on the main rudder blade ( 3 ) and arranged to steering the vessel at high speeds, and that the main rudder blade ( 3 ) is arranged releasable from its fixedly anchored center position, and arranged to be turnable as a whole in the usual manner, especially for steering the vessel at lower speeds.

FIELD OF THE INVENTION

This invention concerns a rudder for water vessels of the kindcomprising a main body and one or more rudder wings arranged to beturned with respect to the main body.

Problem

At low speeds the rudder must have a certain size and angle of attack inorder to steer a vessel efficiently. However, such a rudder may beunnecessarily large for higher speeds, and cause unwanted drag in thesea and thus lost speed and unnecessarily high fuel consumption.Conventional rudders tend to increase their effect almost proportionallywith speed. Large forces are exerted on a rudder that is turned awayfrom the vessel's direction of movement when at high speed. This maylead to damage on the rudder, the rudder stem and the steering engine.During a sudden change of course with a vessel with a conventionalrudder at high speed, a loss of speed occurs.

DESCRIPTION OF THE RELATED ART

Several devices comprising ship rudders and centreboard-like rudderswith rudder wings are known.

U.S. Pat. No. 1,128,508: “Emergency bow rudder” describes a jury rudderarranged in the bow of a vessel and arranged to be thrusted through thebow by means of hydraulics. This jury rudder is arranged to be used incritical situations, e.g. to avoid collision at sea, or if the mainrudder is out of order. The present invention differs from U.S. Pat. No.1,128,528 which does not have a fixedly anchored main body during activeuse, in that the embodiment of the present invention comprises a mainbody which may be drawn in to a fixedly anchored centre position, and inthat the active use of rudder wings causes change of the total rudderprofile and thus a hydrodynamic rudder effect giving a change of courseat high speed.

U.S. Pat. No. 3,326,168: “Retractable rudder for a barge” describes abarge rudder which may be retracted inside an open keel whrereby therudder is hindered from rotation. Thus the rudder does not work whendrawn inside the fixed keel. The purpose and the effect in U.S. Pat. No.3,326,168 thus completely differs from the present invention whereby thesteering effect is entirely present and prepared for high speed, withthe main part of the rudder main body partly drawn back into a rudderblade lock attachment on the hull. U.S. Pat. No. 3,326,168 neither showsnor mentions any kind of movable rudder wings.

U.S. Pat. No. 4,342,275: “Fin rudder for ships” deal with an ordinaryship rudder with one or more flaps at the trailing or astern part of therudder blade, with the flaps arranged to be rotated about a verticalaxle, and arranged to be locked in a fixed position in the main rudderblade.

Norwegian patent 162 452 “High-effect fin rudder for water vessels”,describes a ship rudder with an additional flap which by means of apivoted gear connection to the flap automatically provides an additionalmovement of the flap with respect to the rudder blade. The flap may alsobe locked to the rudder blade.

Solution of the Problem

The present invention relates to a rudder that when used at high speedsis arranged to be attached with its nearest part of the rudder bladefixedly retracted to the vessel's hull, and where the rudder effectproduced by changing the rudder profile by turning the leading flap andtrailing (astern) flap in the direction of the desired turn of thevessel's bow, instead of turning the whole rudder plate to an attackingangle with respect to the direction of speed. In the mentioned retractedposition the turning of the leading and trailing (astern) flap willguide the water current past the rudder in such a way that the waterspeed past the rudder on its two surfaces become different. Thus thepressure effects of the two water currents are that a resultant forcecomponent arises, the force component being normal to the rudder sideand athwart of the water current on the most convex surface at everyinstant. The rudder is fixed to the hull at high speeds by means of atelescopic rudder stem, possibly by additional attaching means. Thisgives the rudder a reduced area within the water current,

SUMMARY OF THE INVENTION

The present invention defines a rudder device of the kind of which theone end is connected to the hull and comprising a main rudder body andone or more rudder flaps which may be turned with respect to the mainrudder body. The new and unique feature of the invention resides in thatthe main rudder body has a fixedly anchored centre position with respectto the hull, with a rudder flap providing the steering effect at highspeeds, and that the main rudder body may be loosened from its fixedlyanchored centre position and arranged to be turned as a whole in theknown way, especially for steering the vessel at low speeds.

More details on new and distinctive characteristics of the embodimentaccording to the invention are found in the patent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described below with reference to the drawings. Severaldistinctive traits and advantages will appear from the description ofdetail in connection to the drawings.

Overview of the Drawings:

FIG. 1 displays a vertical partial cross-section of the vessel and therudder device according to the invention.

FIG. 2 displays the device of FIG. 1 in a side elevation view and avertical section along the vessel.

FIG. 3 is a horizontal section of the rudder device with the turnablerudder flaps in a starboard “lift” force position according to theinvention.

FIG. 4 shows, corresponding to FIG. 3 the turnable rudder flaps in a“lift” force position to the port side.

FIG. 5 displays a partial horizontal view of the upper side of thedevice comprising a stay with a rack and pinion.

FIG. 6 displays schematically a cross-section of the vessel, thesteering engine and the telescopic rudder stem, and a partial elevationview of the rudder in its displaced low-speed position away from thehull, according to the invention.

FIG. 7 displays schematically a longitudinal section of the vessel, thesteering engine and the telescoping rudder stem, and a partial elevationside view of the rudder in its low speed position, displaced away fromthe hull.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates to a rudder that when used at high speedsis arranged to be attached with its nearest part of the rudder bladefixedly retracted to the vessel's hull, and where the rudder effect isproduced by changing the rudder profile by turning the leading flap andtrailing (astern) flap in the direction of the desired turn of thevessel's bow, instead of turning the whole rudder plate to an attackingangle with respect to the direction of motion. In the mentionedretracted position, the turning of the leading and trailing (astern)flap will guide the water current past the rudder in such a way that thewater flowing past the rudder on its two surfaces becomes different.Thus the pressure effects of the two water currents are such that aresultant force component arises, the force component being normal tothe rudder side and athwart of the water current on the most convexsurface at every instant. The rudder is fixed to the hull at high speedsby means of a telescopic rudder stem, possibly by additional attachingmeans. This gives the rudder a reduced area within the water current,thus reducing friction.

At low speed the rudder is pushed in the direction away from the hulland is released from its previously fixedly anchored center position. Bythis release, two mutually cooperating effects arise simultaneously: therudder blade gets a larger effective area in the water current, and themain rudder blade may be turned about the rudder stem as a conventionalrudder. Additional effect of the rudder under low speed is achieved byconventional use of the leading and trailing rudder flaps on the mainrudder blade.

The encasing in the hull provides an increased force load capacity bothin the speed direction and the athwart direction. Retracting the rudderpartially into the hull in an encasing recess also reduces the ruddersurface and thus the friction forces with respect to the water cutthrough by the rudder.

In FIG. 1 the rudder blade is denominated 3 and this has a correspondingrudder stem 8. The vessel's hull 1 has a hull recess 12 wherein therudder may be withdrawn by means of the telescopic rudder stem 8. Therudder stem 8 and thereby the rudder 3 may not be turned when the rudderis withdrawn into the hull recess 12.

FIG. 2 displays a longitudinal section of the hull 1, the steeringengine 10, the rudder stem 8 and the hull recess 12, and an elevationalview of the rudder blade 3 with the substantially vertically journalledbearing held leading and trailing rudder flaps or wings S and 6.

FIG. 3 displays a horizontal section of the rudder with the rudder flapsin a starboard “lift” force position with the leading rudder flap SA andthe trailing rudder flap 6A turned toward the port side. The neutraldirection of the trailing rudder flap 6 is shown. The trailing rudderflap is mounted turnable relative to the axle element 16 (FIG. 5). Thisconfiguration will give the vessel a change of course to the port sideif the rudder is mounted astern.

FIG. 4 shows a section corresponding to FIG. 3, with the rudder flap ina port “lift” force position. This configuration will give the vessel astarboard change of course if the rudder is mounted astern. The rudderflaps here are shown in a starboard position for the leading SB andtrailing 6B positions, with the neutral position 6 shown.

FIG. 5 shows a partial view with the rudder seen from above, with therudder flaps 5, 6 connected with each other by means of crossed steeringrods 21, 22 pivotally connected to the ends of turning cross bars 15A, Battached to the leading rudder flap and 16A, B attached to the trailingrudder flap. The turning movement of the leading and trailing is doneabout the axles 15 and 16. The transmission of force from the commonturning axle 20 is made via a rack and pinion mechanism via one or moreof the steering rods 21, 22. A preferred embodiment has the forcetransmission via a pinion on the turning axle 20 and one of the steeringrods 22.

At low speeds of which one needs a larger efficient rudder area and thussteering effect, the rudder blade according to the invention isdisplaced by means of the telescoping stem 8 from its fixedly heldposition in the recess 12 in the hull 1 as shown in FIG. 6, so that theentire rudder 3, 5, 6 may be turned about the telescoping stem whichnormally is vertical, by means of the steering engine 10.

In a preferred, embodiment the present invention has a slightlytapering-off shape both in breadth and thickness in the direction awayfrom the hull. This tapering-off is preferred in regard to the load thatthe main rudder blade 3 and its fixation is acted on by those forcesthat normally arise on a rudder in high speed, and thus the risk ofbending the rudder in the vertical plane.

Continuing the idea of tapering-off of the main rudder 40 blade 3, butindependent from whether this is tapered-off or not, is to taper off therudder flaps 5, 6 due to the same reason as mentioned above, to reducethe bending forces that may arise on rudder flaps. This possibletapering-off is shown by the numeral 7 in the FIGS. 2 and 7.

The present invention may be embodied as one single main rudder mountedon the vessel, or as a double rudder embodied in two essentiallyparallelly mounted main rudders to achieve the best effect.

The rudder is not limited to an embodiment only as being a ship'srudder, that is, one or more of the ships main rudders mounted astern onthe vessel, but is also possible to apply as horizontally or subhorizontally arranged stabilizing flaps to prevent rolling due to seawaves, and preventing heeling over during a change of course.

The invention is not limited to ship rudders, but also comprises arudder on vessels or underwater gear which may change its depth by meansof a horizontal or subhorizontal depth rudder embodied according to theinvention, or rudders used as balancing rudders, stabilizing rudders andsuch, both in driven and towed or pushed vessels and equipment, such asROV's, submarines and paravanes.

It is evident that the embodiments described in accordance with thedrawings, partially are shown and described in a simplified andschematic form in order to describe the principles of the invention. Inseveral traits of the described constructions there are possibilities toperform modifications and to add construction details and still keep themain ideas and solutions which are brought forward in this invention.

What is claimed is:
 1. A rudder adapted for steering a vessel with ahull, the rudder comprising: a main rudder blade arranged on atelescoping rudder stem; leading and trailing rudder flaps attached tothe main rudder blade, said flaps being turnable with respect to saidmain rudder blade; and said rudder stem being adapted for axialdisplacement of the main rudder blade between a fixedly anchored centerposition, wherein the entire upper edge of the main rudder blade islocked within a recess in the hull and the rudder flaps are turnableindependent of the main rudder blade, and a free turning position,wherein the main rudder blade is positioned away from the hull forordinary turning on the rudder stem; wherein in the fixedly anchoredposition steering is achieved only with the rudder flaps, and in thefree turning position steering is achieved with the main rudder bladeand the rudder flaps.
 2. The rudder of claim 1, wherein said rudderflaps are turnable while the rudder blade is in the free turningposition.
 3. A rudder according to claim 1, wherein the main rudderblade is tapered off to a narrower shape in the direction away from thehull.
 4. A rudder according to claim 3, wherein said taper is withrespect to both width and thickness.
 5. A rudder according to claim 1,wherein the rudder flaps are tapered off to a narrower shape in thedirection away from the hull.
 6. A rudder according to claim 5, whereinsaid taper is with respect to both width and thickness.
 7. A rudderaccording to claim 1, wherein the rudder flaps are mechanicallyconnected by steering rods and arranged to opposite turning movementsforced from a common turning axle.
 8. A rudder according to claim 7characterized by cross-bars attached to each rudder flap with crossedsteering rods pivotally connected to their respective ends of thecross-bars, wherein one or more of the steering rods are connected bymeans of one or more rack and pinion mechanisms with the common turningaxle.
 9. A vessel with a hull and a rudder adapted for steering thevessel comprising: a main rudder blade arranged on a telescoping rudderstem; leading and trailing rudder flaps attached to the main rudderblade, said flaps being turnable with respect to said main rudder blade;and said rudder stem being adapted for axial displacement of the mainrudder blade between a fixedly anchored center position, wherein theentire upper edge of the main rudder blade is locked and the rudderflaps are turnable independent of the main rudder blade, and a freeturning position, wherein the main rudder blade is positioned away fromthe hull for ordinary turning on the rudder stem; further comprising arecess arranged to lock the main rudder blade to the vessel's hull inthe fixed anchored center position.
 10. A method of steering a vesselincluding a hull with a rudder comprising a main rudder blade, leadingand trailing rudder flaps arranged to be turnable with respect to themain rudder blade, and a telescoping rudder stem arranged for axialdisplacement of the main rudder blade between a fixedly anchored centerposition with the rudder blade's entire hull-near end locked to thehull, and a free turning rudder blade position away from the hullcomprising the steps of: fixing said main rudder blade position with therudder blade's entire hull-near end locked in a recess in the hull andturning said flaps for steering at high speeds; and fixing said mainrudder blade position with the rudder in a free turning position forsteering at lower speeds.
 11. A method according to claim 10, furthercomprising the step of at low speeds assisting a turn with both theleading and trailing flaps.
 12. A method as defined in claim 10, furthercomprising the step of moving the flaps so that both flaps turn to thesame side of said main rudder blade.